- Descent with modification was Darwin’s theory on how the Tree of Life was created
- Darwin accounted for extinction and inheritance but did not know about genes or DNA
- The mechanism proposed by Darwin was different from Lamarck
Evolution: Change in the genetic
composition of a population over
Human = ~27 years
Bacteria = ?
Remember: Generations are the timescale for inheritance from parent to offspring
?Proposed that new species could arise from an ancestral form with enough adaptations
Homology =
(1) Individuals in a population vary in their traits
A trait is an observable and measurable characteristic of an organisms phenotype
Trait variation comes from random mutations in the genetic code
(2) Some of these differences are heritable
(3) In each generation, many more offspring are produced than can survive
(4) Individuals with certain heritable traits are more likely to survive and reproduce ( adaptation)
If you were a bacteria today, in 2024….
Humans = ~25 years
Bacteria = ~20 minutes
How long is the average course of antibiotic treatment?
Do you now better understand new variants of SARS-CoV-2?